Aerobic biological purification

Tiiese products, with an oxidation number of 2.5, are presented in the literature as the j final oxidation stage of thiosulfates in aerobic biological purification where enzymes act to- achieve more complete oxidation (autotrophic microorganisms of the thiobacillus thioxidans type). ... 

In aerobic biological purification, the contact with a mass of bacteria can also have a considerable catalytic" effect related to enzyme action. This time the advantage per se would not be a reduction in oxidation time (oxidation rime is governed by the oxidation of OM) but the final SO 4 stage which would be prohibitive by chemical means. 

Sizing activated sludge aerobic biological purification facilities... 

Aerobic biological purification is the only type of purification used in refineries, but petrochemical plants could, albeit rarely, use anaerobic purification by methanization. The general mechanisms, which are the same as for MWW, will not be discussed here but the sizing parameters should be understood. They are calculated based on the following data, as for ASP ... 

Aerobic biological purification, in all cases after H2S stripping, then dilution in the general refinery effluents, or (seldom) in cooling water. This is the most economical and widespread way. 

Spent caustic can therefore be sent to aerobic biological purification after having undergone desulfurization by stripping or by air oxidation and after having been neutralized. 

Primarily, activated sludge processes and, less often, trickling filter processes are employed for aerobic biological treatment. In North America and Northern Europe, effluent purification is frequently carried out in aerated oxidation ponds. Recently, anaerobic treatment has become established, especially in paper mills processing recovered paper. 

The use of catalysts, furthermore, is required in the processes of wastewater purification by reducing treatments. Catalysts also find also application as complementary technologies to other wastewater treatment methods, such as in the control of odour, VOC, N2O and NOx emissions from wet oxidation treatments (for example, in the wet oxidation of industrial sludges), and of odours and VOC emitted from biological processes (aerobic and anaerobic). Although usually commercial catalysts are used in these cases, there are often unpredicted effects in treating complex mixtures and thus more specific catalysts would be preferable. The same is valid for catalysts used to convert stripped VOC from contaminated groundwater. 

Biological waste water purification (aerobic) Onken [109], Deckwer [28]... 

Hydrogen peroxide can also be added in order to stimulate or accelerate aerobic purification, simply by intensifying oxygen supply. Work has shown that this has been effective in dealing with shock loads to biological... 

The commonest method for the purification of liquid effluents including sewage is biological treatment - during the aerobic stage, the low MW halocarbons are probably lost to atmosphere, but not biodegraded. Similarly, chlorinated solvents present in solid waste which is disposed of to landfill will evaporate, over a period depending on the nature of the waste and the type of site operation. 

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